This invention relates to pneumatic tires for vehicles and especially to a tire with a capability for running after unexpected pressure loss resulting from puncture or other tire carcass failure. More particularly, the invention relates to an internal safety structure such as an inflatable tube or resilient toroidal member with special reinforcing means.
Pneumatic tires occasionally become underinflated or completely deflated due to puncture or the like and when this occurs, the deflated or flat tire must be replaced with a spare. In some cases a blowout or other sudden pressure loss can cause the vehicle to go out of control.
Many problems are encountered when operating a vehicle with a deflated or underinflated tire. A deflated or underinflated tire is unstable and makes steering difficult. Often the tire beads unseat and eventually come off the wheel rim. Also, driving a vehicle with a deflated tire causes considerable discomfort to the driver and passengers since there is essentially no cushion between the wheel rim and the road surface. An additional problem is that friction develops between the upper and lower portions of the deflated sidewall of the tire causing the sidewalls to generate heat that results in degradation and/or excessive wear of the two portions.
A tire that can be run after loss of or reduction in pressure has been a desirable objective in the tire industry for some time. A tire that can be run in a deflated condition for an appreciable distance permits the driver to continue after the loss of or reduction in pressure or until a replacement tire can be obtained or the damaged tire repaired. This would eliminate changing tires on the road and the need to depend on the serviceable condition of a spare tire that takes up considerable space in the vehicle. Also, such a safety tire would permit the driver to continue on some distance until a safe stopping place could be found thus avoiding sudden stopping on crowded, streets, bridges and highways. Many pneumatic tire constructions have been designed in an attempt to achieve these capabilities such as the constructions of U.S. Pat. Nos. 3,095,917, 3,392,772 and 3,724,521, however, none have been wholly successful in meeting the operational demands of current automotive vehicles.
The tire construction of the present invention, however, reduces the difficulties indicated above and affords other features and advantages heretofore not obtainable.